Dyestuffs containing chromium and process of making



Patented July 14, 1931 UNITED STATES PATENT oricE KARL HOLZACH, FLUDWIGSHAFEN-ONTHE-RHINE, HANS KAMMERER, 0F MANN- I-IEIM, AND WERNERMINLLER, 0F LUDWIGSHAFEN-ON-IIrIE-RI-IINE, GERMANY, ,AS- SIGNORS '10GENERAL ANILINE WORKS, INC., OF NEW YORK, N. 'Y., A CORPORATION OFDELAWARE DYESTUFFS CONTAINING CHROMIUM AND PROCESS OF MAKING No Drawing.Application filed April 1, 1927, Serial No. 180,337, and in GermanyApril 15, 1926.

It is already known that dyestuffs containing chromium may be producedby treating dyestuffs, which contain chromable groups, with chromiumcompounds, and it has hitherto been the practice to employ the chromiumcompound in such an amount as to provide at least 1 atom of chromium foreach chronr able group in the dyestulf molecule.

We have now found that soluble dyestuffs containing chromium may beobtained, with different properties, by allowing chromium compounds,preferably compounds of trivalent chromium, to act on the dyestuffscontaining chromable groups, in such proportions as to provide less than1 atom of chromium to each chromable group in the dyestuff molecule. Thedyestufis, containing chromium which may be obtained in this way areparticularly distinguished by the 1 difference in their colour shadefrom that of the corresponding dyestuffs when prepared with largeramounts of chromium compound, while retaining the same excellentproperties of the latter in respect to fastness. Thus, the dyeingsobtained with the and with or without the application of pres- LettersPatent No. 151,255 of 1926.

aforedescribed chromium compounds of adyestuffs show practically nochange of shade when acted upon for several minutes at 60 C. with acaustic soda solution containing from 1 to 3 grams of a caustic sodasolution of Be. in each liter of water. The action of the chromiumcompound on the dyestuffmay be brought about in various ways, as forexample accordmg to the exlstmg method,

sure; and also with the addition of a soluble mineral salt of a metalother than those which are known to form metal compounds with thedyestutl, as is described in the application for The following exampleswill further illustrate how the said invention may be carried intopractical effect but the invention is not limited to these examples. Theparts are by weight.

Example 1 The diazo compound from 223 parts of4-chlor-2-aminophenol-5-sulphonic acid is combined in the usual mannerwith 174 parts of 3-methyl-1-phenyl-5-pyrazolone in the presence acaustic soda solution, and, after the coupling is completed, 200 partsof chromium hydroxide containing 26 per cent of @150 and 250 parts of an85 per cent formic acid solution are added to the dyestuif pulp. Themixture is then heated to a temperature of 120 C, for from 3 to 4 hours,in a pres sure vessel fitted with stirrers. The resulting chromiumcompound of the azo dyestuif is converted into the readily solublesodium salt by treatment with a caustic soda solu tion. This salt givespure red'dyeings on wool from an acid bath. The free tinctorial acidcrystallizes in well defined needles, with a green metallic luster, froma mixture of alcohol and water, which needles contain 2 atoms ofchromium to 8 molecules of dyestuff.

The corresponding dyestuff prepared, accord-V ing to the previouslyknown method, with larger amounts of chromium, contains 1 atom ofchromium to each molecule of dyestulf, and dyes wool. red shades with adecidedly more yellow tinge.

Emampile 2 10 parts of the dyestuflt' from the diazo compound ofl-nitro-Q-aminophenol-(i-sulphonic acid and betanaphthol are boiled;

with 500 parts of a solution of chromium formate, containing 4.2 partsof Or O for 20 hours under a reflux condenser. The salted-out and drieddyestuif gives black dyeings, of excellent fastness, on wool,

Analysis reveals that the dyestufi containing chromium contains 2 atomsof chromium to every 3 molecules of dyestuff. The dyestufli' containingchromium prepared according to the previously known method with double2. The process of producing dyestufi's containing chromium whichconsists in treating an azo dyestufi' containing chromable groups with acompound of trivalent chromium in such a roportion .as to provide lessthan 1 atom of chromium to each chromable group in the dyestuflmolecule.

--3. As a new product, the complex chromium-containing compound of thechro- 10 mable dyestufi having the probable formula containing chromiumin the proportion of substantially 2 atoms of chromium to 3 molecules ofthe chromable dyestufi', which compleX, chromium-containing compoundcrystallizes in well-defined needles having a green, metallic lusterand, in the form of its sodium salt, dyes wool from an acid bath purered shades.

3 In testimony whereof we have hereuto set our hands.

' KARL HQLZACH.

HANS KAMMERER.

WERNER

